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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236/* SPDX-License-Identifier: GPL-2.0 */#ifndef __LINUX_PAGE_EXT_H#define __LINUX_PAGE_EXT_H
#include <linux/types.h>#include <linux/mmzone.h>#include <linux/stacktrace.h>
struct pglist_data;
#ifdef CONFIG_PAGE_EXTENSION/** * struct page_ext_operations - per page_ext client operations * @offset: Offset to the client's data within page_ext. Offset is returned to * the client by page_ext_init. * @size: The size of the client data within page_ext. * @need: Function that returns true if client requires page_ext. * @init: (optional) Called to initialize client once page_exts are allocated. * @need_shared_flags: True when client is using shared page_ext->flags * field. * * Each Page Extension client must define page_ext_operations in * page_ext_ops array. */struct page_ext_operations { size_t offset; size_t size; bool (*need)(void); void (*init)(void); bool need_shared_flags;};
/* * The page_ext_flags users must set need_shared_flags to true. */enum page_ext_flags { PAGE_EXT_OWNER, PAGE_EXT_OWNER_ALLOCATED,#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT) PAGE_EXT_YOUNG, PAGE_EXT_IDLE,#endif};
/* * Page Extension can be considered as an extended mem_map. * A page_ext page is associated with every page descriptor. The * page_ext helps us add more information about the page. * All page_ext are allocated at boot or memory hotplug event, * then the page_ext for pfn always exists. */struct page_ext { unsigned long flags;};
extern bool early_page_ext;extern unsigned long page_ext_size;extern void pgdat_page_ext_init(struct pglist_data *pgdat);
static inline bool early_page_ext_enabled(void){ return early_page_ext;}
#ifdef CONFIG_SPARSEMEMstatic inline void page_ext_init_flatmem(void){}extern void page_ext_init(void);static inline void page_ext_init_flatmem_late(void){}
static inline bool page_ext_iter_next_fast_possible(unsigned long next_pfn){ /* * page_ext is allocated per memory section. Once we cross a * memory section, we have to fetch the new pointer. */ return next_pfn % PAGES_PER_SECTION;}#elseextern void page_ext_init_flatmem(void);extern void page_ext_init_flatmem_late(void);static inline void page_ext_init(void){}
static inline bool page_ext_iter_next_fast_possible(unsigned long next_pfn){ return true;}#endif
extern struct page_ext *page_ext_get(const struct page *page);extern struct page_ext *page_ext_from_phys(phys_addr_t phys);extern void page_ext_put(struct page_ext *page_ext);extern struct page_ext *page_ext_lookup(unsigned long pfn);
static inline void *page_ext_data(struct page_ext *page_ext, struct page_ext_operations *ops){ return (void *)(page_ext) + ops->offset;}
static inline struct page_ext *page_ext_next(struct page_ext *curr){ void *next = curr; next += page_ext_size; return next;}
struct page_ext_iter { unsigned long index; unsigned long start_pfn; struct page_ext *page_ext;};
/** * page_ext_iter_begin() - Prepare for iterating through page extensions. * @iter: page extension iterator. * @pfn: PFN of the page we're interested in. * @count: maximum number of page extensions to return. * * Must be called with RCU read lock taken. * * Return: NULL if no page_ext exists for this page. */static inline struct page_ext *page_ext_iter_begin(struct page_ext_iter *iter, unsigned long pfn, unsigned long count){ if (!count) return NULL;
iter->index = 0; iter->start_pfn = pfn; iter->page_ext = page_ext_lookup(pfn);
return iter->page_ext;}
/** * page_ext_iter_next() - Get next page extension * @iter: page extension iterator. * @count: maximum number of page extensions to return. * * Must be called with RCU read lock taken. * * Return: NULL if no next page_ext exists. */static inline struct page_ext *page_ext_iter_next(struct page_ext_iter *iter, unsigned long count){ unsigned long pfn;
if (WARN_ON_ONCE(!iter->page_ext)) return NULL;
if (++iter->index >= count) return NULL; pfn = iter->start_pfn + iter->index;
if (page_ext_iter_next_fast_possible(pfn)) iter->page_ext = page_ext_next(iter->page_ext); else iter->page_ext = page_ext_lookup(pfn);
return iter->page_ext;}
/** * page_ext_iter_get() - Get current page extension * @iter: page extension iterator. * * Return: NULL if no page_ext exists for this iterator. */static inline struct page_ext *page_ext_iter_get(const struct page_ext_iter *iter){ return iter->page_ext;}
/** * for_each_page_ext(): iterate through page_ext objects. * @__page: the page we're interested in * @__pgcount: how many pages to iterate through * @__page_ext: struct page_ext pointer where the current page_ext * object is returned * @__iter: struct page_ext_iter object (defined in the stack) * * IMPORTANT: must be called with RCU read lock taken. */#define for_each_page_ext(__page, __pgcount, __page_ext, __iter) \ for (__page_ext = page_ext_iter_begin(&__iter, page_to_pfn(__page), __pgcount); \ __page_ext; \ __page_ext = page_ext_iter_next(&__iter, __pgcount))
#else /* !CONFIG_PAGE_EXTENSION */struct page_ext;
static inline bool early_page_ext_enabled(void){ return false;}
static inline void pgdat_page_ext_init(struct pglist_data *pgdat){}
static inline void page_ext_init(void){}
static inline void page_ext_init_flatmem_late(void){}
static inline void page_ext_init_flatmem(void){}
static inline struct page_ext *page_ext_get(const struct page *page){ return NULL;}
static inline struct page_ext *page_ext_from_phys(phys_addr_t phys){ return NULL;}
static inline void page_ext_put(struct page_ext *page_ext){}#endif /* CONFIG_PAGE_EXTENSION */#endif /* __LINUX_PAGE_EXT_H */